package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * @Author: 滴滴滴
 * @CreateTime: 2025-03-21
 * @Description: 使用Redis生成唯一ID
 * @Version: 1.0
 */
@Component
public class RedisIdWorker {

    private static final int COUNT_BITS = 32;
    /*
    * 开始时间戳
    * */
    private static final long BRGIN_TIMESTAMP = 1735689600L;

    private StringRedisTemplate stringRedisTemplate;
    public RedisIdWorker(StringRedisTemplate stringRedisTemplate){
        this.stringRedisTemplate = stringRedisTemplate;
    }

    public long nextId(String keyPrefix) {
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BRGIN_TIMESTAMP;

        //2.生成序列号
        //2.1获取当前时间，精准到天
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2自增长
        Long count = stringRedisTemplate.opsForValue().increment("icr" + keyPrefix + ":" + date);
        //3.拼接并返回
        return timestamp << COUNT_BITS | count;
    }

/* 这里算出开始时间戳：1735689600 ，以2025年1月1日0小时0分0秒为准
   public static void main(String[] args) {
        LocalDateTime time = LocalDateTime.of(2025, 1, 1, 0, 0, 0);
        long second = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println("second = " + second);
    }*/
}
